caa a22 4500 467885737 CHVBK 20180406152733.0 cr unu---uuuuu 170328e20060601xx s 000 0 eng 10.1007/s10021-005-0114-6 doi (NATIONALLICENCE)springer-10.1007/s10021-005-0114-6 Nutrient Enrichment and Planktonic Biomass Ratios in Lakes [Elektronische Daten] [Dag Hessen, Bjørn Faafeng, Pål Brettum, Tom Andersen] Phosphorus (P) to chlorophyll ratios and zooplankton-phytoplankton (Z:P) biomass ratios were assessed in 400 temperate lakes over a gradient of phosphorus (P) and with different fish communities. Most of the lakes in this survey were oligotrophic, with a median total P of 7.3μg P L−1. Thus, the survey provided information on food web effects during the early phase of eutrophication. There was no tendency toward a reduced yield of autotrophs per unit of P over the gradient covered in this survey. The zooplankton yield per unit of P or chlorophyll a decreased slightly with increased nutrient concentrations, and Z:P biomass ratios decreased with fish community classes, reflecting increased fish predation pressure. However, the variability in biomass ratios within a given range of P and fish class was some 100 times higher than the difference over the gradients. This finding suggests that lake-specific properties, community composition, and food quality are by far the most important determinants of biomass ratios and probably also trophic efficiency in lakes; it further suggests that these factors are superimposed on the general effect of eutrophication, at least up to 30μg P L−1. Springer Science+Business Media, Inc., 2006 nutrient enrichment nationallicence trophic levels nationallicence phytoplankton nationallicence zooplankton nationallicence fish nationallicence lakes nationallicence Hessen Dag Department of Biology, University of Oslo, P.O. Box 1027, 0316, Blindern, Oslo, Norway aut Faafeng Bjørn Norwegian Institute for Water Research (NIVA), P.O. Box 173, 0411, Kjelsås, Oslo, Norway aut Brettum Pål Norwegian Institute for Water Research (NIVA), P.O. Box 173, 0411, Kjelsås, Oslo, Norway aut Andersen Tom Department of Biology, University of Oslo, P.O. Box 1027, 0316, Blindern, Oslo, Norway aut Ecosystems Springer-Verlag; www.springer-ny.com 9/4(2006-06-01), 516-527 1432-9840 9:4<516 2006 9 10021 https://doi.org/10.1007/s10021-005-0114-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-005-0114-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Hessen Dag Department of Biology, University of Oslo, P.O. Box 1027, 0316, Blindern, Oslo, Norway aut NATIONALLICENCE 700 1- Faafeng Bjørn Norwegian Institute for Water Research (NIVA), P.O. Box 173, 0411, Kjelsås, Oslo, Norway aut NATIONALLICENCE 700 1- Brettum Pål Norwegian Institute for Water Research (NIVA), P.O. Box 173, 0411, Kjelsås, Oslo, Norway aut NATIONALLICENCE 700 1- Andersen Tom Department of Biology, University of Oslo, P.O. Box 1027, 0316, Blindern, Oslo, Norway aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/4(2006-06-01), 516-527 1432-9840 9:4<516 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer